436 research outputs found
Dosimetric characterization of CVD diamonds irradiated with 62 MeV proton beams
Diamond is potentially a very suitable material for use as on-line radiation dosimeter. Recent advances in the synthesis of polycrystalline diamond by chemical vapor deposition (CVD) techniques have produced material with electronic properties suitable for dosimetry applications. In this work the possibility to use a segmented commercial CVD detector in the dosimetry of proton beams has been investigated. The response as function of dose, dose rate, the priming and the rise time have been investigated thoroughly. This study shows the suitability of CVD diamond for dosimetry of clinical 62 MeV proton beams. r 2005 Elsevier B.V. All rights reserved
Gas radon emission related to geodynamic activity on Mt. Etna
We report preliminary observations on possible correlations between anomalies of subsoil radon concentration
and geodynamical events on Mt. Etna. In recent years several studies have been carried out on radon as a precursor
of geophysical events, most of them performed either on tectonic or volcanic areas. The peculiarity of our
investigation lies on the choice of the etnean region, in which tectonic and volcanic features are both present.
In order to characterize Mt. Etna features by investigating radon gas in soil, two stations were located along the
NE-SW direction on Mt. Etna. Each of the two stations is fitted with a radon detector, a 3D seismic station and
a meteorological station. Differences in the radon concentration trend in the data from north and south flanks
could be linked to different faulting mechanisms and then to different mechanisms of radon uprising. The increase
in soil radon concentration could be related to both seismic and volcanic events
A single amino acid change A19V in perforin: a novel, frequent predisposing factor to childhood acute lymphoblastic leukemia?
We screened 100 children with acute lymphoblastic leukemia (ALL) to assess the incidence of single amino acid change A91V in perform. Heterozygous A91V was found in 12/100 patients and 5/127 controls (OR, 3.4; 95%CI: 1.15-9.95; p=0.014). A91V is a novel and frequent predisposing factor for childhood ALL
Scanning Probe Microscopy on heterogeneous CaCu3Ti4O12 thin films
The conductive atomic force microscopy provided a local characterization of the dielectric heterogeneities in CaCu3Ti4O12 (CCTO) thin films deposited by MOCVD on IrO2 bottom electrode. In particular, both techniques have been employed to clarify the role of the inter- and sub-granular features in terms of conductive and insulating regions. The microstructure and the dielectric properties of CCTO thin films have been studied and the evidence of internal barriers in CCTO thin films has been provided. The role of internal barriers and the possible explanation for the extrinsic origin of the giant dielectric response in CCTO has been evaluated
Dosimetric characterization of CVD diamonds in photon, electron and proton beams
The purpose of this work is the characterization, in an on line configuration, of the dosimetric response of a commercial CVD diamond. The study shows the possibility of using CVD diamond for dosimetric purposes with clinical, high-energy electron (4-15 MeV), photon (6-15 MV) and proton (62 MeV) beams
Indoor and soil radon measurements in the Hyblean Foreland (South-East Sicily)
Indoor radon behavior in two sites of SE Sicily was studied as a function of the soil radon concentration. The
chosen locations were Ragusa and Modica towns, placed in the Hyblean Plateau (northern margin of the African
Plate). Soil samples were analysed by gamma spectrometry to determine the amount of radionuclides. Indoor air
and soil gas radon measurements were simultaneously performed in both sites using active detectors. Radon in
soil was measured one meter deep. A positive correlation was obtained between indoor radon concentration and
the soil gas concentration
Indoor and soil radon measurements in the Hyblean Foreland (South-East Sicily)
Indoor radon behavior in two sites of SE Sicily was studied as a function of the soil radon concentration. The
chosen locations were Ragusa and Modica towns, placed in the Hyblean Plateau (northern margin of the African
Plate). Soil samples were analysed by gamma spectrometry to determine the amount of radionuclides. Indoor air
and soil gas radon measurements were simultaneously performed in both sites using active detectors. Radon in
soil was measured one meter deep. A positive correlation was obtained between indoor radon concentration and
the soil gas concentration
CATANA protontherapy facility: The state of art of clinical and dosimetric experience
After nine years of activity, about 220 patients have been treated at the CATANA Eye Protontherapy facility. A 62MeV proton beam produced by a Superconducting Cyclotron is dedicated to radiotherapy of eye lesions, as uveal melanomas. Research and development work has been done to test different dosimetry devices to be used for reference and relative dosimetry, in order to achieve dose delivering accuracy. The follow-up results demonstrated the efficacy of proton beams and encouraged us in our activity in the fight against cancer
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